None of those parties I’ve referred to is giving you an honest story. A careful set of explanations will show you that GMO crops (as they are cultivated today) are no riskier than any other produce and are generally not consumed directly by humans. That’s why the whole “GMO free” label is a bit of a swindle; it’s a marketing trick designed to prey upon the ignorance of how GMOs are grown and used.

Which crops are genetically modified?

Very few crop species, but we grow large quantities of the crops that are genetically modified. GMO soy, corn, cotton and canola are grown at a massive scale but nothing you get from the fresh produce section in your grocery store has been modified. Almost all the soy, corn and cotton we grow is either Monsanto’s “herbicide tolerant” or “insect tolerant” type. There are a few others (like Hawaiian papaya) but most of these are grown at much smaller scales and the reasons those are modified are very different from the major GMO crops.

Why are crops genetically modified?

Agriculture is a resource intensive practice, but not all agriculture products go into human mouths. Crops have been genetically modified to reduce the amount of input resources (including energy, water, pesticides etc.) required to grow them (i.e. to lower costs). Most of this crop volume is itself an input into products like beef, fuel and textiles.

The United States grows a lot of soy and corn. Only about 20% of the soy and 12% of the corn is actually eaten by people and a lot of it is in the form of fairly non-essential foods (corn chips, salad dressing etc.). We grow this stuff because humans like meat (which isn’t a very energy efficient way to grow food) and because governments have policies about fuel production. A lot of people think growing corn for fuel is a really stupid idea.

The principle genetic modifications in GM crops come from inserting genes from common soil bacteria, genes that we do not believe pose a risk to human health. Insecticide resistance is introduced from inserting a inspect-specific toxin gene from Bacillus thuringiensis, which we discovered after using crystals of the bacterial spores as a safe and effective insecticide. Herbicide resistance is introduced by using a gene from Agrobacterium tumefaciens. This specific bacterial species contains a gene which allows plants to break down the herbicide glyphosate, and has machinery to insert this DNA into plant cells.

A molecule of glyphosate, image from wikipedia.

Glyphosate is widely acknowledged as a remarkably safe and effective weed killer, and health concerns are centered on farm workers (who are exposed to many many hazards), not consumers. Both of these common soil bacteria may well be part of the humanmicrobiome. Nothing is ever completely certain in science, but it is very hard to imagine how the existing products from GMO crops could be harmful to human health, and if they were, we would expect the same of many natural and traditional agricultural products.

Am I eating any GMO crops?

Probably not directly, as the corn we eat in the summer isn’t the same cultivar grown for animal feed. It’s possible the edamame in your local grocery store could be GMO.

Since we grow so much corn and soy, it is really tempting to take some of the refined products (starches, oil etc.), throw some sugar and salt on it and put it in some brightly colored packaging with a celebrity endorsement. Processed food products (think anything that you buy in a box: chips, cereal bars, etc.) are where these crops get into our mouths in the most significant way. The products from GMO crops that are used in processed food products aren’t necessarily bad, but they just tend to be marketed in products that you could probably live without.

This isn’t merely some corn meal fried in soybean oil with some salt on it, it is “…the idea of Doritos Collisions mixing those great flavors is an original idea — just how I like my music” – Missy Elliot

Are GMO crops bad for human health?

Any diet related questions have to be answered very carefully, since diet science is fraught with a notorious amount of uncertainty. The common sense answer is “no”, GMO crops are not dangerous to human health and we have no reason why we would predict they would be.

One could make a crop with a genetic modification that is quite poisonous, but GMO crops are not about poisoning people. I wish I could say that it is an absurd notion that a society would plant a crop at a large scale to poison people, but we do have tobacco and alcohol which humans enjoy for their stimulant effects at the cost of significant health risk.

You are almost certainly already exposed to the products of the transgenic genes in GM crops (as they come from common soil bacteria) and we have a good understanding of how those genes work and we cannot predict why they would be harmful. GMO crops have also been carefully tested in animals and we don’t see any significant effects. There are plenty of natural things to be worried about when it comes to agriculture (salmonella, listeria, alphatoxin), heck, the natural trypsin inhibitors in raw soybeans will make you quite sick if you eat them without treating them with “wet heat”. It is hard to rationalize a food system that outright poisons its consumers at large scale.

Golden rice.

The “golden rice” project is a cause célèbre of GMO foods. The consortium behind the project has managed to insert two genes into rice that enable the production of β-carotene, giving it a golden hue. The aim of the project is to address vitamin A deficiency in developing countries with lacking diets. A really interesting fact about golden rice is that after inserting two of the expected three genes we expected it to be red, since they only provided the pathway to lycopene (the red in tomatoes) and not all the way to β-carotene. It turned out that rice already expressed the (previously undiscovered) third gene and could produce β-carotene with just the first two genes, a testament to Nature’s messy ball of partially maintained genetic spaghetti code. The project has made some remarkable improvements in vitamin A yield and its aims are commendable but it remains to be seen how effective it will be in addressing vitamin A deficiency in the real world. It is hard to argue against the idea that golden rice could be an effective solution and worth trying.

Can GMOs help eliminate world hunger?

We have plenty of food security in the “developed world” and animal agriculture demands we spend far more in terms of resources (energy and water) on food than we need to.

One might think that lowering production costs could help address hunger in developing countries but it is important to remember that world hunger has relatively little to do with production capacity. World hunger has much more to do with things like distribution policies, storage technology, colonial history and water security. Oxfam has a good introduction.

GMOs do not do much in terms of solving hunger; human societies use hunger as a method to ensure certain people are conveniently prevented from pursuing many of the benefits we enjoy in the developed world. Perhaps if we can introduce a gene into our crops that makes the people who eat it more likely to share resources there is a chance for more direct impact.